Mechanical Property Comparison of Hemp and Flax Fiber Reinforced Polylactic Acid versus Additive-Enhanced and Carbon Fiber Reinforced Polylactic Acid in Fused Deposition Modeling

Abstract

Fused deposition modeling (FDM) is a common additive manufacturing (AM) technology. This study compares PLA reinforced with natural fibers (hemp, flax) to modified PLAs: PLA Plus (additive-enhanced) and PLA CF (synthetic carbon-fiber reinforced). Mechanical behavior is assessed via tensile, compression, and impact tests, complemented by microscopy-based microstructural analysis to evaluate performance differences in detail experimentally. The findings of the study indicate that, in impact and compression tests, PLA Plus offers the best performance, showing a 15.278 KJ/m2 in the average energy per surface for the impact test and, an elastic modulus of 1.69 GPa and yield stress of 85.7MPa, while PLA hemp exhibited values that were either equal to or highly comparable to those obtained by PLA CF. In the tensile tests, the PLA CF shows the best results, the modulus value obtained was 6.69 GPa, exhibiting a modulus value that was 146.30% higher than that of the PLA hemp and 167.37% higher than that of the PLA flax. Finally, a thorough examination of the scanning electron microscopy (SEM) images revealed that the observed properties could be attributed to a reduced number of bubbles and a higher proportion of reinforcement fibers when compared to the natural fibers (NF) filaments examined.